The invention relates to a weaving heddle which is suitable, in particular for a jacquard weaving machine.
Jacquard weaving machines use, as a rule, weaving heddles that are resiliently suspended on one end. A cord, the so-called harness cord, is attached to the other end, said cord leading to a jacquard machine. This machine applies a specific tension to the cords, as a result of which the heddles are moved individually and independently of each other. Regarding details of jacquard weaving machines, reference is made to document DE 101 24 022 A1. This type of heddle actuation has reached its limits, considering the operating speeds of modern weaving machines. In order to control the heddle and its mass, increasingly stronger springs must be used with increasing speed. This stresses jacquard weaving machines unnecessarily. In addition, the potential use of stronger springs is limited due to the confined spatial conditions.
For example, CH Patent 631 755 has already suggested to produce a weaving heddle of plastic material, in which case this weaving heddle was not intended for jacquard weaving machines but for use on heald shafts that comprise two parallel heddle-mounting rails on which the weaving heddles are held—with play—by their end eyes. The weaving heddle known from this document comprises a body of plastic material in which a mail is set so as to form an eye for a thread. This mail consists of an annular body of a material which is harder than the plastic material. On its outside circumference, this body has a continuous, flat groove, whereby said body extends into said groove. In addition, the body of plastic material extends around the edges of the mail in order to secure it in place in a form-closed manner.
This type of weaving heddles is not directly suitable for jacquard weaving, in which the weaving heddles are permanently tensioned between the harness cord and the spring.
Furthermore, document EP 0 403 429 A1 suggests a weaving heddle for use on heald shafts that have two heddle-mounting rails, on which the ends of the heddles are seated. The heddles can slide freely on the heddle-mounting rails, i.e., they display great lateral movability. Consequently, the weaving heddles can yield to the warp threads passing between said heddles, thus restricting the friction between the warp threads and the weaving heddles. The weaving heddles known from said literature reference consist of a plastic/fiber composite material. In order to produce this material, a tubular braid is embedded in a plastic material matrix. This tubular braid is covered by the plastic material. In order to form a thread eye, a mail is set into the thusly formed heddle body.
Referring to the weaving heddles of the two documents CH 631 755 and EP 0 403 429, the heddle body is thicker in the region of the mail, whereby two straight legs extend from said mail in this thicker region. The transition from one leg to the thicker thread eye region is formed by a short ramp-like section. This section, in particular, is subject to wear, i.e., material abrasion, when warp threads graze along the heddle. If, due to such wear, the fibers of the plastic/fiber composite material are exposed, the reinforcement fibers projecting from the plastic body can thus damage the warp threads.
Considering the above, it is the object of the invention to provide an improved, light-weight heddle suitable for jacquard weaving.